80
How units of volume are related
Textbook: Part 3, lesson 80, pp. 37–39
GoalHow units of volume are related: 1 l = 1 dm³ = 1 000 ml, 1 ml = 1 cm³, 1 m³ = 1 000 dm³.
New words
litre · litr (l)millilitre · millilitr (ml)vessel · idishcapacity · sig‘im
Explanation
The volume of liquids is measured in litres. A cube box with edge 1 dm (10 cm) holds exactly 1 litre of water: 1 l = 1 dm³ = 1 000 cm³. There are 1 000 millilitres in a litre, so 1 ml = 1 cm³. Large volumes are measured in cubic metres: 1 m³ = 1 000 dm³ = 1 000 l. Between neighbouring units of volume the number changes by a factor of 1 000.
Worked examples
6 dm³ = 6 l = 6 000 cm³; 4 l = 4 000 ml.
2 l 400 ml = 2 000 ml + 400 ml = 2 400 ml = 2 400 cm³.
Class activity
“The one-litre box”: a cube box with edge 10 cm is made from card, filled with water and poured into a litre jug to check that 1 l = 1 dm³.
Practice
1
7 l = ? ml
7000
2
7 000 dm³ = ? m³
7
3
3 m³ = ? l
3000
4
How many millilitres of water fit into a cube-shaped vessel with edge 5 cm?
125
5
A kitchen has juice in 25 two-litre bottles and 12 five-litre bottles. How many litres of juice is there in total?
110